Chapter 22, Immune System, TTC Objectives Bio 211
List the 4 steps of inflammation.
1) release of inflammatory and chemotactic factors (histamine, heparin, basophil responses) 2) Vascular changes (vasodialation and increased permeability of vessels for immune cells to transport from blood to interstitial fluid) 3) Recruit leukocytes and immune cells (diapedesis, chemotaxis) 4) delivery of plasm proteins(complement, immunoglobulins, clotting proteins, kinins)
Explain secondary response of adaptive immunity.
2nd exposure, short latent period because antibody levels rise rapidly
What is adaptive immunity
Acquired immunity, involves specific T and B cells that respond to antigens. Usually takes several days to be effective. The cells involved are so specific that what responds to the chicken pox virus is not the same cell that responds to the flu virus.
Define AIDS and explain how it differs from HIV.
Acquired immunodeficiency syndrome/HIV is the virus that causes AIDs. It destroys Helper T cells so the body cannot produce new antibodies or stimulate Cytotoxic T cells
_____ ______ results from direct encounter with pathogens, can be attained naturally and artificially.
Active Immunity
Describe Antigenic Determinate
Also known as epitope. it is a specific site on anitgens that the immune system recognizes and lymphocytes connect with
Explain IgD
B cell receptors, maybe ready for ?????need to do more research
Humoral Immunity is form B cells or T cells?
B cells
How are B cells activated?
B cells make contact with antigen, phagocytizes it and displays it on MHC II to present the antigen to Helper T cell, then waits for Helper T cell response. Interlukin 4 is released from Helper T cell if antigen is recognized. Interlukin 4 stimulates B cell to clone itself. Some of the clones become memory B cells and others become antibody factories that release antibodies into blood to initiate an immune response.
Describe Basophils.
Circulate in the blood. A chemotactic cell whose main goal is to attract other immune cells during inflammation and to bring fluid from blood into interstitial fluid, release histamine, heparin and eicosanoids.
Describe receptor complex.
Each T and B cell has a unique receptor complex, a site on the cells that is 1 specific receptor that binds to 1 specific antigen. T cell receptor complexes are referred to as TCR and B cell receptors are known as BCR
Explain IgM antibody
First responder, found in blood, only antibody produced in fetus
How are Cytotoxic T cells activated?
First, CD8 of Cytotoxic T cell Binds to MHC I and TCR binds to the antigen of infected cell. Second, Interlukin 2 from Helper T cell stimulates the Cytotoxic T cell to clone into memory T cells and activated/effector cytotoxic T cells
How are Helper T cells activated?
First, direct physical contact between antigen presenting cell and a helper T cell must happen (for inspection). If the Helper T cell does not recognize the antigen it will disconnect and move on. If it does recognize the antigen, contact with the cell can last several hours. Second, the Helper T cell secretes cytokines (interlukin 2) to stimulate cloning of activated/effector Helper T cells and Memory T cells
Explain IgE
Found in blood, produced during allergic reactions/parasites from mast cells and basophils. Attract eosinophils
Name the 5 immunoglobulin classes.
IgG, IgA, IgM, IgD, IgE
What chemicals are released from Helper T cells to activate/stimulate B cells, Helper T cells, and Cytotoxic T cells?
Interlukin 2 (T cells) and interlukin 4 (B cells)
Why are there 2 different types of Major Histocompatibility Complex?
MHC I is the MHC for body cells (non immune cells) it displays self antigens in a healthy cell. Lets say a virus attacks the cell, then the cell will take little pieces of the virus and attach them to MHC I. Cytotoxic T cells will see the foreign pathogen and perform apoptosis MHC II are used for immune cells such as B cells and T cells It displays pieces of pathogens on its surface intended for inspection and maybe distruction by T cells
What mechanism do antigen presenting cells use to display either self antigen or pieces of engulfed/phagocitized pathogens?
Major Histocompatibility complex. MHC is like glue or a display case, holding pieces of either self antigen or pathogens to show your immune system cells so they can eithe attack or ignore. There are 2 types of MHC: MHC I (on cytotoxic T cells) and MHC II (on helper T cells)
Define IgG antibody
Major class of antibody, located in body fluids, used for passive immunity and can cross placenta (can cause new born hemolytic disease)
What are the 6 different cell types of innate immunity?
Neutrophils, Macrophages, Basophils, Mast Cells, Natural Killer Cells, Eosinophils
Define Autoimmune Disorders.
Occur when the immune system does not have a tolerance for self antigen so initiates an immune response
______ ______ is obtained from another individual, can be obtained naturally and artificially.
Passive Immunity
When a B cell is activated and cloned into an effector B cell, they are called_________?
Plasma Cells
Explain primary response of adaptive immunity.
Primary response is first time infection to new pathogen, then a latent phase of 3-6 days while B cells are in pathogen detection, B cell activation and proliferation and differentiation. Then plasma cells produce antibodies (IgM and IgG) that peak (known as Titer) then decrease
Describe Mast Cells
Reside in multiple and various body tissues. Similar to a Basophil. A chemotactic cell whose main goal is to attract other immune cells during inflammation and to bring fluid from blood into interstitial fluid, release histamine, heparin and eicosanoids.
Describe Macrophages.
Reside in the tissues through out the body. Are the second responders in an inflammatory response but they stay longer than Neutrophils. Main job is phagocytosis.
Describe T cell maturation.
T cells have CD4 and CD8 on their plasma membranes when they leave red bone marrow and travel to thymus. If they have both CD4 and CD8 then the T cells will not work properly. In the thymus, T cells go through tests to help them differentiate into Helper T cells and Cytotoxic T cells
Cell-mediated immunity is from B cells or T cells?
T cells. It is when cytotoxic T cells release perforin and granzymes to induce apoptosis.
What is negative selection?
Tests immature T cells in thymus, check to make sure they do NOT bind to self antigens. This is tested by self presenting thymus cells. If they bind to self antigens they get destroyed, immature T cells learn to ignore self antigens
What is positive selection?
Tests immature T cells to check if it can bind to MHC. If it binds to thylamic MHC molecules it will survive, if not then they will die
Describe Membrane Attack Complex.
The compliment system can only kill pathogens through MAC, otherwise they can only assist other leukocytes in attacking pathogens. Compliments kill pathogens by forming a protein plasma channel in the plasma membrane of a target cell. The hole in the cell causes structural damage and allows an influx of fluid that causes the cell to lyse.
Describe Neutrophils.
The most prevalent Leukocyte in blood. It is the first responder in an inflammatory response. The main component in puss. Its main objective is to phagocytize antigens and debris.
What is the shape of immunoglobulins?
Y shaped
Do T cells require antigen presenting cells?
Yes, T-cells are activated by the presentation of antigens on the plasma membrane of other cells. They cannot do their job without another cell to first eat the pathogen, break it apart, then present the small pieces of the antigen on its cell surface, waiting for a T cell to bind to it and begin an immune response or ignore it.
Are all nucleated cells of the body antigen presenting?
Yes, body tissue cells present self antigens which stop T cells from killing them, unless the cell becomes cancerous or infected and then the tissue cell will present the infection and cancerous cells on their plasma membrane. In which case the T cells will attack. Immunce cells are also antigen presenting and are used to activate T cells to destruct and replicate to fight pathogens
Explain the function of interferons (IFNs)?
a non-specific antimicrobial protein (cytokine) released from a variety of cells that is a non-specific mechanism against the spread of viruses. 2 primary actions: 1) IFN binds to neighboring cells to prevent them from becoming infected while releasing enzymes that attack viral DNA so that it cannot reproduce 2) IFN stimulates macrophages and NK cells to destroy virus infected cells
What is an antigen?
a substance that binds to a component of adaptive immunity (remember adaptive immunity includes antibodies, B cells and T cells)
Define Allergy
an acute hypersensitivity, an over reaction of the immune system to noninfectious substances
What is inflammation?
an immediate, local, nonspecific response to injury. It is the major response of innate immunity because it is effective in helping eliminate most infectious agents and unwanted substances in body.
Immunoglobulins are ______?
antibody proteins
Describe Natural Killer Cells.
apoptosis initiating cells. Can destroy a wide variety of cells. NK cells release perforin which forms a pore in antigen for ganzymes to enter and kill cell. NK cells reside in tonsils, spleen, lymph nodes (secondary lymphatic structures). The NK cells patrol the body.
Antidote shots from snake bites or ebola is an example of ____________. Where antibodies are removed from the blood of a previous survivor and injected into a newly exposed patient.
artificially acquired passive immunity
Explain IgA
in external secretions, like tears, saliva, mucus, skin. Helps protect against GI and respiratory infections
Your immune system fighting the flu virus is an example of ________?
naturally acquired active immunity
Breast Feeding is an example of ________?
naturally acquired passive immunity
What is innate immunity?
non-specific, you are born with it. So, it does not require previous exposure to a pathogen to work. Includes skin, mucosal membranes, and stomach acid that act as the first line of defense. Also includes non-specific cellular defense, such as granulocytes and NK killer cells, which are the bodies second line of defense.
Describe Eosinophils.
parasite destroying cells, releases chemicals that create a membranous pore in parasite and destroy it. It is a cell that is also associated with allergies and asthma responses.
Describe Fever.
part of innate immunity, 2nd line of defense (innate immunity) fever is an abnormally elevated body temp (1 degree Celsius above norm at 37 degrees Celsius, or 1.8 degrees above 98.6 degrees Fahrenheit).
How is the compliment system activated?
pathogens enter the body, then compliment proteins bind to antibody in 2 different ways: 1) classical pathway: the compliment protein binds to an anitbody that was previously attached to a foreign subtance 2) alternative pathway: the compliment protein binds directly to the cell wall of a pathogen and does not require a pathogen
What role do pyrogens play during fevers?
pyrogens are toxins produced by infectious agents, trauma, tumors or drug reactions. Pyrogens are released, then circulate thru blood, then go to the hypothalamus, the hypothalamus then releases prostaglandins which tells hypothalamus to raise the body temp. set point. There are 3 phases of a fever 1) onset 2) Stadium (the duration of time the body temp is elevated) 3) Defervesence (when pyrogens are no longer being produced the hypothalamus stops producing prostaglandins and thus ends the fever cycle)
What are 4 signs of inflammation?
redness, heat, swelling, pain
What is the compliment system?
similar to IFNs with the following differences: it is 30 different types of plasma proteins collectively called compliment because they 'compliment' or assist antibodies. They are made in the liver and released into the blood as inactive until they are activated by an enzyme cascade.
What is the purpose of a plasma cell?
they are anitbody factories, their job is to produce antibodies that can act on pathogens from a distance. Like a flag or a marker for the T cells to find
What is an example of artificially acquired active immunity?
vaccines
What part of an immunoglobulin is the site for specific antigen binding?
variable region
What is immunologic memory?
when memory cells have a 2nd exposure to antigens (secondary response) and can act quickly and eliminate pathogen before symptoms set in. This makes adaptive immunity a potent protector and why vaccines work.